deezul Posted January 4, 2011 Share Posted January 4, 2011 Random no start, usually occurs when hot. truck surges slightly at stop lights/signs (surging remedied by icp sensor). Monitored ICP pressure and voltage, voltage was slightly erratic, inspected ICP sensor and harness. Sensor leaking and pushing oil up pigtail, replaced sensor and pigtail. Performed audible hpo test, could not hear any air leaks, verified that IPR was switching correctly when manually commanded. Issue still present after repair. Monitored PIDs when issue present, found FICM SYNC and SYNC not correlating. Sync and RPM present with no start, FICM SYNC not always present. No codes in system, performed resistance test on cam and crank sensors (within spec), inspected for rust jacking behind cam sensor, performed diesel cam timing with oscilliscope and found no issues with patterns/waves. Disconnected banks tunning system, issue still present. No codes present in system, truck has no driveability concerns and performs well on road test. Customer states that the issue is only present when hot but it is so erratic that it's hard to duplicate and verify if "temperature" plays a role in this issue. ICP voltage w/no start present ranges between 1.5-1.9v Pressures range between 1400-1900psi IPR ramps to 85% when cranking (when FICM_Sync isn't prsent) and slowly drops down 10% until Ficm_Sync is reached or until cranking has ended. Having issues determining what is causing the FICM_Sync issue..is there any diag I missed performing? Any tips? Quote Link to comment Share on other sites More sharing options...
mchan68 Posted January 4, 2011 Share Posted January 4, 2011 Engine harness. Quote Link to comment Share on other sites More sharing options...
deezul Posted January 4, 2011 Author Share Posted January 4, 2011 What makes you say engine harness? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted January 4, 2011 Share Posted January 4, 2011 Over the years we have seen many harness problems - here, the take outs for the cam and crank sensors drop down from the top front of the engine and route behind the front accessory bracketry where the convolute wrapping becomes brittle from heat and falls apart. This exposes the wires and allows chafing to occur. Since you have problems with CMP/CKP and sync it seems likely the harness is causing your problems. Quote Link to comment Share on other sites More sharing options...
deezul Posted January 4, 2011 Author Share Posted January 4, 2011 Alright. Makes sense. I haven't had much experience with harness issues and was just trying to get on the same wave length. I load tested the cam and crank circuits from the sensors to the pcm and from the pcm to ficm. Wiggling and tugging on harness still renders me with no results.. Ill spend a few more minutes but engine harness seems to be the general consensus... Quote Link to comment Share on other sites More sharing options...
deezul Posted January 4, 2011 Author Share Posted January 4, 2011 Any chances this could be a ficm issue? Quote Link to comment Share on other sites More sharing options...
mchan68 Posted January 5, 2011 Share Posted January 5, 2011 Any chances this could be a ficm issue?Have you monitored FICM volts during all this (particularly FICM_M)? Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted January 5, 2011 Share Posted January 5, 2011 Seems to me I once uploaded the FICM diag guide... can't remember the title but it had to do with SYNC/FICM SYNC no start diagnosis... Anyone remember or should I try to post it again? Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted January 5, 2011 Share Posted January 5, 2011 It's over there<<<<<<<< in the coffee table book section. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted January 5, 2011 Share Posted January 5, 2011 Quote: tugging on harness still renders me with no results I would be wary of getting to physical with 6.0l engine harnesses. They are pretty fragile to begin with and you may end up creating more problems than it originally came in with.As these things get more complicated with more sensors and more wiring, the wiring harnesses get larger and heavier. So what do they do? They make the wire smaller. Instead of 16 and 18 gauge wires in the past now we have 20 and 22 gauge wires. Take this and put it into an extremely harsh and vibration induced enviroment and it's a disaster waiting to happen. I have lost count of all the little broken wires we have seen going here and there on these engines. We get lucky and find them and lots of times it just gets a harness. Sometimes it's cheaper on the labor, ya know? I cringe everytime I see someone with the intake off and the wiring harness pulled tight over the fan stator. Quote Link to comment Share on other sites More sharing options...
deezul Posted January 5, 2011 Author Share Posted January 5, 2011 Monitored FICM voltages during concern, no issues found, (12.5/48.5/12.5)...that didn't seem like a good enough answer for tech line though as they want me to install spare ficm to "give it a try"...I do not own a "known good ficm" nor do we have any six ohs on the lot that I can rob one from. Ive been sent down some wonky paths by tech line before and I just don't want to be wasting my time..... Quote Link to comment Share on other sites More sharing options...
mchan68 Posted January 5, 2011 Share Posted January 5, 2011 Monitored FICM voltages during concern, no issues found, (12.5/48.5/12.5)...that didn't seem like a good enough answer for tech line though as they want me to install spare ficm to "give it a try"...I do not own a "known good ficm" nor do we have any six ohs on the lot that I can rob one from.I didn't think a FICM would be an issue either, by what you're describing. Originally Posted By: deezul Ive been sent down some wonky paths by tech line before and I just don't want to be wasting my time.....I couldn't agree more about the time wasting part...... That's why my initial reply to this thread was to put a harness in it and be done with it. I believe Alex Bruene posted a while back that you can have these trucks in with some weird issues, pull the harness out and apart, only NOT to be able to find any problem areas that you can see by eye, but put a new harness in and the problem is fixed. Quote Link to comment Share on other sites More sharing options...
deezul Posted January 5, 2011 Author Share Posted January 5, 2011 That's more than fair. As mentioned earlier I haven't had much "harness" experience (only on econolines, my cherry will be popped if/when I put a harness in this f-series).... I wish I could prove it was the harness before putting one in it. Then again I had an e-series where I couldn't prove it was a harness until I put one in it, nothing better than contradicting myself. Thanks again for your help guys! Quote Link to comment Share on other sites More sharing options...
mchan68 Posted January 5, 2011 Share Posted January 5, 2011 That's more than fair. As mentioned earlier I haven't had much "harness" experience (only on econolines, my cherry will be popped if/when I put a harness in this f-series).... I wish I could prove it was the harness before putting one in it. Then again I had an e-series where I couldn't prove it was a harness until I put one in it, nothing better than contradicting myself. Thanks again for your help guys! If reassurance is what you're looking for, hear this one out. You know how there are some vehicles, that you get coming in regularly where you NEVER have issues and everything goes smoothly? And then you get the ones that come in that EVERY time you have to wrench on it, just about every fastener or component fights you all the way to the end of the job. Well, I had one such truck, a 2004 F-Series (with a 2003 engine). He's a good customer that comes in regularly for ALL work that's needed. I replaced an ICP sensor and connector about two years ago to repair a P2285 and engine surging symptoms. Fast forward 80,000 kms., and the truck is back with the same issue, only it's on an intermittent basis. Since I had already replaced the pigtail connector and it drove 80,000 kms. without issue, I doubt workmanship is playing any kind of role in its second failure. The customer REQUESTED for me to replace another sensor and the whole engine harness this time around. New harness and sensor later, no issues (and we did call the customer back to follow up on it, after the repair). Quote Link to comment Share on other sites More sharing options...
deezul Posted January 7, 2011 Author Share Posted January 7, 2011 I've learned that it's alot nicer changing a harness on an fseries than an econoline (huh, go figure...lol)...I hadn't had any issues after harness install until I came back from lunch and went to move the truck back into the shop, no start Ficm sync vs. sync is still wonky. Recommended doing cam and crank sensors when replacing harness, so those have been changed now as well (although resistances and the signal pattern were both well within spec). FICM sync still equals no when sync equals yes. I even inserted screw driver into crank hole and try to wiggle the tone ring, no success. Now I'm really, really, really running out of ideas... It's not temperature related and the truck will usually start after you key off and then attempt again... Quote Link to comment Share on other sites More sharing options...
mchan68 Posted January 7, 2011 Share Posted January 7, 2011 Which harness did you replace? The ENGINE (12B637) harness or the FICM (9D930) harness? Quote Link to comment Share on other sites More sharing options...
deezul Posted January 7, 2011 Author Share Posted January 7, 2011 Replaced the engine harness Mr.Chan 12B637...going to swap in a known good PCM, wish me luck. Quote Link to comment Share on other sites More sharing options...
mchan68 Posted January 7, 2011 Share Posted January 7, 2011 Replaced the engine harness Mr.Chan 12B637...going to swap in a known good PCM, wish me luck.What happens when you wiggle test the 9D930 harness? Swapping in a PCM is very quick and easy but I doubt a PCM will cause what your describing. Quote Link to comment Share on other sites More sharing options...
deezul Posted January 8, 2011 Author Share Posted January 8, 2011 I wiggled the carp out of the harness, still no luck. PCM swap was a dud, part #'a weren't the same and the pcm was from a newer truck, it pretty much turned every light on the dash and it wouldn't start... although my scope pattern was good I may just drop the pan and take a peak at the tone ring I'm happy it's Friday, I'm even happier that I still have a couple of christmas gift cards for the beer store, perhaps when Im a bakers dozen in I will have some sort of epiphany... Quote Link to comment Share on other sites More sharing options...
mchan68 Posted January 8, 2011 Share Posted January 8, 2011 If your DVOM is capable of reading in Hz, you can connect them to the CKP and CMP circuits by snipping off the old pigtails from the harness and using them. You should be seeing 150 to 200 Hz from the CKP circuit, directly proportional to engine RPM and 1.1 to 1.9 Hz for the CMP circuit when the engine is cranking over. Those are specs that Hotline gave me one time. I know it likely won't help you with telling you if cam and crank are in time, but by virtue of the fact that the engine runs I doubt base engine/valve timing is of any issue here. Quote Link to comment Share on other sites More sharing options...
deezul Posted January 8, 2011 Author Share Posted January 8, 2011 I checked for these values at the pcm connector, for some odd reason I am not getting any signal from my CAM circuit, crank is directly proportional to cranking rpm...man I wish tech line would have told me these numbers then maybe Id be getting somewhere by now... Quote Link to comment Share on other sites More sharing options...
Jeff_E Posted January 8, 2011 Share Posted January 8, 2011 No cam signal to PCM after already replacing sensor and harness? How rusty is your engine block? Any chance there's enough rust on the block to prevent the CMP from having a proper air gap? CLICK HERE About half way down this post for a picture from Keith to see if it may apply to your situation. Quote Link to comment Share on other sites More sharing options...
mchan68 Posted January 8, 2011 Share Posted January 8, 2011 No cam signal to PCM after already replacing sensor and harness? How rusty is your engine block? Any chance there's enough rust on the block to prevent the CMP from having a proper air gap? Jeff beat me to it. I was wondering the exact same thing. But I figured Scott had already checked those items BEFORE replacing the harness and CMP. Quote Link to comment Share on other sites More sharing options...
deezul Posted January 8, 2011 Author Share Posted January 8, 2011 Yeah, I may be somewhat novice but I'm not that novice <shaking head>. I have seen rust jacking on that sensor a dozen other times so I made sure that the block is bare and shiny, I even removed the o-rings off the sensor just to be 100% certain that the gap was proper. I don't understand how I had a good pattern on my silly scope but now trying to retrieve a frequency, no dice. I guess I will go in tomorrow and see if I can see anything sinister from camshaft sensor port, see if maybe the timing pin or something is worn... Quote Link to comment Share on other sites More sharing options...
deezul Posted January 8, 2011 Author Share Posted January 8, 2011 So here's my hypothesis, this might sound crazy and I have been drinking but take a read: Worn out camshaft bearings Here's why. Signal comes and goes...How does it? The peg isn't missing for the camshaft because it does start, I did grab a good pattern on my silly scope but currently I can't grab a frequency. When it's cold the oil is good and thick and keeps the cam floating and let's it start without issues. When it's hot the oil is good and thin and can barely keep das cam a float causing the signal to come and go. The cam walking back and forth throwing out the air gap would cause this uber random YES signal/ NO signal. This truck also has a banks system on it, extra stress?? Reasons why I might be crazy: I have no driveability concerns. You'd think at wot and how minute the air gap is between the sensor and the cam peg I would have stalling and/or driveability concerns..but I don't (it did surge at stop lights/signs but the new ICP sensor fixed that). So am I crazy or am I onto something????? Anyone on some sort of brain wave that I am or is it the Gibsons talking? Quote Link to comment Share on other sites More sharing options...
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